IPhone passcode time?

I'm a cell phone dinosaur who just recently got his first smart phone. I have a hand-me-down old iphone 5 I think. I'm getting frustrated always having to put in my pass word so often when I use it. I understand and appreciate the purpose of it, but wish I could extend the time it remains idle before it requires me to punch it in again. Is this possible, and if so how?

Is it possible to sell a high dollar item on ebay without getting scammed?

I read about a person who sold an iphone and lost all their money AND phone because this buyer claimed it had "water damage" without even showing evidence. And ebay didn't even make them ship the item back.
I read if you make them sign a delivery confirmation they can't make false claims on you? But I don't know. Or you can have them write you a check? But i don't know if ebay even allows checks anymore. These couple of items I want to sell are over $200 and they are more "specialty" collectible items so selling them on CL would be a bit tough, someone would most likely buy it just to sell it for a little more on ebay, lol.

Instagram won't let me go live with friends?

I have an iPhone 6 with the latest version of Instagram and it just won't let me go live with friends, I'll start a live and it won't have the button to invite a friend, and if someone requests me I'll accept and it will just say waiting and nothing will happen, anyone know wat to do I also had the same problem with the 5c